Batteryless remotely powered devices, such as RF identification transponders (RFID tags), are well known in the industry. These devices employ coils or RF antennas to couple to a fixed or handheld base station transmitter which sends out power and/or signals as electromagnetic waves. Such devices use an AC power circuit that converts the AC power received by the antenna to a DC voltage level. The DC power is then used to power the circuit or circuits in the remotely powered device. In order for the devices in the circuits to work, the DC voltage level generated by the AC power circuit must be above a certain minimum level. To extend the range of these devices, the antenna or coil is resonant with the electromagnetic field, and the front-end circuits are typically resonant with the AC coil or RF antenna. Historically, these front-end circuits are simply diode rectifiers, full-wave rectifiers, or voltage doubling circuits.
Voltage multiplier circuits with multiplication of greater than two are well-known in the art of digital circuits. Such circuits have been proposed, but have not been used in to provide voltage multiplication in remotely powered devices such as RFID tags operated at high frequencies above 2 Ghz.